Electrical preheater for carburetors



N 19, 1935. R. STEINHART Er AL 2,021,525

ELECTRICAL PREHEATBR FOR CARBURETORS Filed Aug. 9. 1934 Dre/Liam.-

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Patented Nov. 19, 1935 OFFICE ELIC'l'I-IOAL PREHEATIB FOB OABBUBETOBS Rudolf 'Stclnhart. Vienna, Austria, and Anna Hunter, Berlin, Germany .Appliea tionfillgusti. InGennany 1834, Serial 0. 789.118 April 11, 4

scum. (c1. zis-ss) It is a known thing to prdieat air for the carburetors of explosion engines in order to achieve better running of the engine. The preheating is eilected by the most varying means, it being for example usual to place the suction pipe for the carburetor around the exhaust pipe in order to take the preheated air from there. It is also known to heat the carburetor air by electrical means.

The heating spirals which efiect the heating of the air in this way are fixed in the suction piping so that the air is always obliged to brush past the heating spirals. even at times when it would be more advantageous not to efiect any preheating. The heating spirals themselves are constantly exposed to the strong suction air of the engine, that is, of the carburetor.

The present invention has as its object the overcoming oi this disadvantage by making it possible for the electric preheater to be liftedat will, possibly by a Bowden cable control operated from steering column or dash. out of the area of the suction pipe. By inserting an intermediate piece in the suction pipe in the place oi the electric preheating element, which corresponds in size to the gap. the carburetor suction pipe can then be closed again.

As the element is raised out of or lowered into the suction pipe of the carburetor the electric current is switched ofl and on respectively, by automatic action. I

A device is also provided that makes it possible for the exhaust gases, in the case of a misfire. not to pass through the sensitive heating spirals but to be led before reaching the latter through a flap valve provided in the suction pipe. which valve is automatically opened by the heavy pressure 01 the escape. thus making possible extensive saving of wear as regards the heating spirals. In the accompanying drawing the object of the invention is depicted.

Fig. 1 shows the carburetor in front elevation with the heating device raised.

Fig. 2 is a side view oi the same.

Fig. 8 is a diagrammatic elevation. partly in section.

Fig. 4 shows the heating element holder, front view and Fig. 5 shows a side view in section on the line v--v oi Fig. 4.

In the interrupted suction pipe to the carburetor is located the heating element container 3.

freely moveable in a housing i, to which container 3 is fixed below a pipe ll of the same section asthesuctionpipe. Thispieceoi'pipingiland the vehicle. The

the preheater i joined can be raised and lowered by a cable control 2| operated from the steering column of the vehicle. The heating element container I consists 01' two insulating halves 21, the. heating spirals II lying deeply embedded in these 5 halves. The ducts 24 form a connection between the two beds. The heating elements 21 are insulated by mica plates against each other and against the lid ll of the heating element. The v slots It provided in thae plates enable the pass sage of the air sucked up. On the wall 22 oi the heating element sits an insulating piece It through holes bored in which the ends II of the heating wires lead to connecting screws II and II. The connecting screw ii lies in apiece of tubing 28 and there a ball 2 under the pressure of a spring is fitted, which ball acts as a contact for the circuit. At a corresponding depth an insulating disc 4 is located in the'housing I, in the centre of which disc is inserted a metal piece I! in such a way that it does not touch the inner edge of the housing 2 butstands at a short distance from it and is insulated in respect of the heating element container 3. On lowering the preheater container the contact with the ball 2 to is established through the connection screws it and thus the heating spiral is placed under current.

The slots II, which have already been mentioned, are so distributed that at every length 30 of a longitudinal slot one winding oi the heating spiral is omitted. In this way loss oi heat in the heating spirals is avoided, as the current 01' air sucked up is exposed to the heat over the whole oi its extent. The pipe I leads behind the housing i to the actual carburetor. The pipe 5 has a flap valve 6 which is under the pressure of a spring 1 and serves the purpose of allowing the passage oi the gases when the engine misfires.

The method or working of the object oi the 111- vention is the following:-

If the preheater is to be brought into operation the piece oi piping 20 and thus the electrical heating element housing I is pulled down. by pulling the wire 2i from thesteering column oi heating element housing I is then located between the pieces of piping I and I! and through the contact ball I the circuit is completed for the heating spirals through the contact piece IT. The current passes through the contact screw It to the metal piece l1 and through the contact ball I to the contact screw Ii fitted in the piece of piping it. to which screw II the end 8| of the heatingwire is joined. The other end of the heating wire is connected through one of the screws II to the motor mass. If it is required to put the electrical preheater out of action, this also is done from the steering column of the vehicle by means of the wire II, which on operation presses upwards the piece of piping 26 and thus also the heating element container 3, with the aid or the spiral spring I. Thus the circuit is also broken by the contact ball I. By means of the piece of piping I! lying between the pieces of piping 5 and 29, this piece ll corresponding in length to the gap in the piping caused by the heating element container, the smooth section in the suction pipe is once again established. The flap valve pressed down by the spring 1 on to the slot I prevents damage to the preheater when switched on, that is to its heating spirals, in the case of misnring, as the exhaust gases are led out through the flap valve I which opens owing to the pressure.

We claim:-

1. An electrical preheater tor carburetors or internal combustion engines comprising an interrupted suction pipe,a movable section of piping normally filling the gap to complete the suction pipe, an electrical heater member attached to said section of piping, means ior connecting said electrical heater to an electric circuit, means for moving said section of piping out o! the suction pipe, the electrical preheater automatically moving to flll the gap and means for completing the electric circuit energizing the preheater.

2. In an electrical preheater for carburetors 0! internal combustion engines as claimed in claim 1, a cover to the heating member, heating spirals in said cover, slots in said cover, one slot being eliminated at every winding length 01 said heating spirals.

3. In an electrical preheater for carburetors of internal combustion engines as claimed in claim 1, an outwardly opening safety valve located in the section of piping for escape of mming exhaust gases.

RUDOLF STEINHART. ANNA HUNTER. 

